Slide resistance



May 5, 1970 i H. EBERWEIN ETAL 3,510,321

SLIDE RESISTANCE Filed May 31, 1968 my. I

/4 I Q i 4 4 ,5 /Z -20 12 7 10 3 7 3 In ventars United States Patent US. Cl. 338-183 14 Claims ABSTRACT OF THE DISCLOSURE A slide resistance having a housing composed of two identical halves of thermoplastic material, each half providing: first and second guide grooves for slidingly receiving a slide and a closing strip; integrally formed first pins (pegs or studs) and holes matchingly arranged to engage one another for connecting the halves with each other; integrally formed second pins, pegs or studs adapted for the attachment of a resistor bar, a bus bar, and soldering tabs; chambers between the two halves near their ends on different faces and adapted for the reception of nuts serving for the securement of the slide resistance; integral third connecting pins, taps or studs and corresponding recesses for the in-series arrangement of a plurality of such resistances; recesses for the provision of shielding sheets between several resistances; and openings at the ends of the first guide grooves for the slide, such openings being adapted for the passage of connecting members between the slide and an outwardly arranged switch.

THE FIELD OF THE INVENTION AND THE PRIOR ART The invention relates to the type of slide resistances as they are used more and more, mainly in entertainment electronics. These slide resistances should be obtainable for a low price and should have the smallest possible dimensions.

Slide resistances are known having housings formed of one piece of sheet metal or as zinc die castings, and being provided with guiding means for a double-armed slide spring, the arms contacting a resistance layer and a bus bar of metal and additionally with two round rods or acentral flat rod. A disadvantage of these slide resistances is that they are composed of relatively many individual parts so that their assembly requires a great deal of work.

THE OBJECTS OF THE INVENTION The main object of the present invention is to provide a slide resistance which consists of a few individual parts only and which may be produced and assembled with very little work.

A further object of the invention is the provision of a slide resistance which permits easy in-series connection with similar resistances and which may be used for simultaneously actuating an adjoining switch.

THE FEATURES OF THE INVENTION The aforesaid objects are achieved in accordance with the present invention by the simultaneous provision several or all of a plurality of several features, some of them having been known per so.

More specifically, the invention consists in a slide resistance combining several or all of the following features:

(1) A casing consisting of two substantially identical half-shells formed of thermoplastic material;

(2) Provision of a first guide groove for the reception of the arms of a slide on the inner side of the shell-halves;

(3) Matching first studs, pegs or pins and holes integrally formed on the shell-halves for extending the pegs into the holes and connecting the shells with each other by heat pressing the peg heads into the holes or by forming the pins or pegs as snap-in connectors;

(4) Further, second pegs integrally formed on the shell-halves and adapted for entering holes of a resistor strip, a bus bar, and connector tabs so as to secure the latter by heat offsetting said pegs;

(5) A second guide groove formed in the halves presenting a closed figure for the reception of a continuous sealing-band of metal or plastics, said band being adapted to close a slot for the slide;

(6) Chambers formed between the two halves on the end faces and on the upper and lower faces of the shellhalves for the reception of nuts, the nuts being adapted for the securement of the slide resistance to an adjoining structure;

(7) Further, third matching pegs and oppositely arranged holes on the outsides of the shell-halves for inseries arrangement of a plurality of resistances;

(8) Further, fourth retainer pegs and a recessed space formed integrally on the shell-halves for the lateral arrangement of shielding metal sheets; and

(9) Passages on the end faces of the shell-halves formed in continuation of said first guide grooves for the slide and being adapted for the reception of connecting elements between the slide and an adjoining switch.

BRIEF DESCRIPTION OF THE DRAWING The present invention and its details are described in the following as an example by means of an embodiment illustrated in the attached drawing, in which:

FIG. 1 shows a plan view of a slide resistance upon removal of one of the half-shells; and

FIG. 2 represents a vertical cross section through the completely assembled slide resistance, the section being taken in a plane normal to the direction of movement of the slide.

DETAILED DESCRIPTION OF THE DRAWING The housing of the slide resistance consists essentially of two substantially symmetrical and identical half-shells 1 and 1' of thermoplastics, such as obtainable under the trade name Durethan. The shells are provided symmetrically as to the plane aa with locating first tabs, studs or pins 9 and matching oppositely arranged holes 10 so that upon assembly of the two half-shells with each other the studs 9 enter into the holes 10. In the illustrated embodiment, the studs 9 project beyond the holes 10 and have their projecting ends offset by the application of heat and pressure so as to connect the two half-shells with each other. Upon appropriate formation of the stud 9 as snap-in studs or pegs, a releasable connection between the two shell-halves may be obtained.

A resistance element 2 is located in the right hand halfshell 1 which, in the illustrated embodiment, consists of an insulating strip carrying a resistance layer and is provided with clamped-on soldering tabs 3 as input and output connectors. The resistance element 2 is secured to the half-shell 1 by second pegs or studs 11 integrally formed on said shell-half, entering into holes provided in element 2 and having their ends heat offset. Instead of a resistance element with a resistance layer, a so-called coil strip having a resistance wire wound onto an insulating strip may be placed into the half-shell 1.

A metallic contact strip or bus bar 12 is correspondingly secured by pins or studs 11 to the other half-shell 1'. Soldering tabs 3, which might also appropriately be 4. For this purpose, slide 4 is provided with arms which,

upon assembly of the half-shells 1, 1 with each other, enter the grooves and assure easy and play-free sliding movement of the slide.

A substantially U-shaped contact spring 19 is secured to slide 4, e.g. by means of an offset pin of slide 4 entering into a hole of the web of the U-spring. Contact spring 19 has its arms provided with oppositely directed contacts, the one contact, preferably a carbon contact 20, engaging the resistance element 2 and the other contact being formed by a cup-shaped projection which engages the slide bar or bus bar 12.

Slide 4 is formed with a handle which extends through an appropriately shaped opening in a closed-figure or continuous band 8. This band 8 slides in closed-figure groove 7 formed in the two shell-halves 1, 1' and thereby provides for a complete sealing-off of the slide slot in any position of the slide.

For combining the slide resistance with a switch, the end faces of the half-shells 1, 1 are provided at the ends of the guide grooves 5 with passages 6 through which lateral push rods of a special slide (not illustrated) may outwardly project in the starting and/or end position of the slide and may co-operate with a corresponding actuating element of a switch.

Nuts 14 serve for screw-securing the slide resistance. These nuts 14 are inserted into chambers 13 before the assembly of the two half-shells, one half of each of these chambers 13 being formed in each of the half-shell. So as to permit securement of the slide resistance at its different sides, these chambers are provided on both ends of the shells in three directions offset with respect to each other by 90 each.

The outer walls of the half-shells 1 and 1 are provided with or form, respectively, symmetrically to the axis aa third pegs, pins or studs 15 and matching oppositely arranged openings 16 serving together for positioning and connecting two or more slide resistances in side-by-side arrangement (duplicate or tandem resistances).

Shielding metal sheets (not illustrated) may be provided on the individual resistances, which are received in spaces formed by recesses 17 in the outer walls of the shells and held by studs 15.

The invention is not restricted to the structural details of the illustrated and described embodiment but is to cover all such modifications and adaptations as will easily occur to those skilled in the art and which are within the scope and the spirit of the attached claims.

What is claimed is:

1. In a slide resistance, comprising in combination: a casing having two substantially identical half-shells of thermoplastic material; a first guide groove on the inner side of each half-shell adapted to receive the arms of a slide; first matching pegs and recesses integrally formed on said half-shells and adapted to fit into each other and the pegs to be anchored in said recesses; second pegs integrally formed on said half-shells and adapted to enter into holes of a resistor strip, a bus bar and soldering tabs, respectively; a second guide groove formed in said halfshells, presenting a closed figure and being adapted to receive a sealing band for closing a slide slot provided between the two halves; chambers adapted to receive nuts and provided at the end faces and at the opposite upper and lower faces of the half-shells; third matching outwardly projecting pegs and recesses integrally formed on the shells for in-series arrangement of adjoining slide resistances; fourth retaining pegs and recessed spaces for thelateral attachment of shielding metal sheets; and passages extending through the half-shells at the ends of said grooves adapted 0t receive and guide said slide, said passages permitting the location of connecting elements between the slide and adjoining switches.

2. In a slide resistance according to claim 1, in which said pegs are secured in said holes and recesses by heat offsetting.

3. In a slide resistance according to claim 1, in which said first pegs are formed as snap-in connectors.

4. In a slide resistance, a casing comprising two substantially identical half-shells of a thermoplastic material.

5. In a slide resistance according to claim 4 having said half-shells providing with first guide grooves on their inner sides, said grooves being adapted to receive a contact slide.

6. In a slide resistance according to claim 4 having matching first pegs and holes formed on said half-shells, said pegs being adapted to enter into said holes.

7. In a slide resistance according to claim 6 in which said first pegs are heat offset for securement in said matching holes.

8. In a slide resistance according to claim 6 in which said first pegs are formed as snap-in pegs.

9. In a slide resistance according to claim 4 integrally provided with second pegs adapted to enter into holes formed in a resistor element, a bus bar, and connector tabs, respectively, and to secure same to the respective one of said half-shells.

10. In a slide resistance according to claim 5 forming second closed-figure continuous guide grooves adapted to receive a flexible band for closing a slot formed between said half-shells adjoining said first guide grooves.

11. In a slide resistance according to claim 1 having chambers formed near the end of said casing between said half-shells, said chambers being provided at the upper, lower and end faces of the casing and each being adapted to receive a nut.

12. In a slide resistance according to claim 4 having said half-shells integrally provided with third pegs and recesses adapted for in-series arrangement of a plurality of casings.

13. In a slide resistance according to claim 4 having said half-shells provided on their outsides with fourth retaining pegs and with recesses for the lateral arrangement of shielding metal sheets.

14. In a slide resistance according to claim 5 having passages provided in said half-shells, said passages extending through the walls of the shells in continuation of said first guide grooves and being adapted to slidingly receive connector elements between said slide movably arranged in said first guide grooves and a switch arranged outside of said casing.

References Cited UNITED STATES PATENTS 3,362,004 1/1968 Bang 338183 3,358,259 12/1967 Kirkendall 338183 3,221,131 11/1965 Bury 200168 3,329,793 7/1967 Camp 200-168 LEWIS H. MYERS, Primary Examiner A. T. GRIMLEY, Assistant Examiner US. Cl. X.R. 

